The big rhinestones are called acrylic flatback rhinestones. The size haloheaven.com uses for the center of their gerberas is 22mm I believe. I have some 12mm flatback rhinestones and those look good on the smaller hydrangea blossoms. I just bought some 4mm hotfix & that size looks good for adding small rhinestones to the centers of bows.

Some woodburners will accommodate hotifix tips. I have a walnut hollow woodburner & the kandi cane hotfix tips will work in it.